YES, a sofa is for lounging. But if you are Ellen Barkin, you work it like a prop. In her trailer last week on the Warner Brothers lot, where she is filming “Ocean’s Thirteen,’’ Ms. Barkin settled into its cream-colored leather cushions, shifting by degrees from an upright posture to a slouch, then kicking off her Louboutin slingbacks and sliding into full recline.

Pensive and chatty by turns, she spoke with a candor more commonly heard on an analyst’s couch. She has plenty to talk about: the new film, in which she plays the female lead opposite Brad Pitt, Matt Damon and George Clooney, and which reunites her with Al Pacino, her co-star in “Sea of Love,” the 1989 thriller that was a career-making showcase of her sex appeal.

Then there is her personal life, which has been turned inside out since the abrupt end of her marriage to the financier Ronald O. Perelman in January.

The breakup was tabloid-ready: Mr. Perelman’s lawyers surprised her with the news that he was seeking a divorce, and he had security guards stand by while she moved out of their regal townhouse on East 63rd Street. Much of the six-year marriage between the billionaire and the movie star seemed to play out in public because of the couple’s prominence, though its essence remained a mystery.

Now Ms. Barkin, 52, has chosen an equally public denouement by putting up for auction the extravagant jewelry that Mr. Perelman lavished on her, having decided to part with more than 100 pieces valued at $15 million — a symbolic and literal purging of the union.

“These are just not memories I want to wear out every day,’’ Ms. Barkin said.

The trove, to be sold at Christie’s in Rockefeller Center on Oct. 10, includes a 32-carat apricot diamond ring that Mr. Perelman, who is the chairman of Revlon, gave Ms. Barkin weeks before their divorce; a pair of emerald and gold cuffs designed for the Duchess of Windsor, valued at up to $80,000; an emerald necklace that once belonged to Doris Duke that could fetch as much as $350,000; and a selection of pieces by the cult Parisian jeweler JAR. Only 80 to 90 JAR creations are produced each year, said François Curiel, the chairman of Christie’s Europe. “When you have 17 pieces of JAR in an auction, it’s an event.’’

For Ms. Barkin, the sale puts a seal of finality on her relationship with Mr. Perelman, whose wish to be single again caught her unawares, she said. A divorce granted by a Manhattan court a few weeks later left her with $20 million under the terms of a prenuptial pact.

That fortune notwithstanding, the rupture left Ms. Barkin feeling raw. Her ex-husband’s behavior “was shocking,’’ she said. “What I thought was a commonality was a very different bond.’’

Ms. Barkin said a confidentiality agreement prevents her from discussing aspects of the marriage. But in an interview meant to focus on the auction of her jewelry, she did not censor her feelings about the breakup and described some of its causes and the nature of her marriage. Mr. Perelman, through a spokeswoman, declined to respond or otherwise comment.

Ms. Barkin said the marriage was founded on genuine affection. “I loved Ronald Perelman,’’ she said. “I can say that unequivocally.’’ Mr. Perelman, she suggested, had struck a cooler bargain.

In his mind, she said, “I was an accessory, being accessorized, the perfect one — age-appropriate, the mother of two children, successful in her own right.’’

As an actress Ms. Barkin was known for steamy performances in movies like “The Big Easy” and “Switch.’’ Yet she was also the attentive mother of two children by the actor Gabriel Byrne, and projected an aura of matronly respectability. “I was an actress who for 20-some years had never left her children once to do a movie,’’ Ms. Barkin said. “That looked good.’’

“And you know I wasn’t a bimb,’’ Ms. Barkin said, less with rancor than regret. “I was a good get.’’

She said that Mr. Perelman did not want her away from his side for the months it takes to make a movie, so except for small parts, she put her career on hold. “When I met Ronald Perelman I wasn’t going to travel,’’ she said. “That made it more difficult to work, but that was kind of fine with me.’’

Some 18 months ago, Ms. Barkin accepted a cameo in “Ocean’s Twelve,’’ the sequel to “Ocean’s Eleven,’’ a role requiring her to spend 36 hours on a film set in Chicago. Her part was later cut, but it caused a rupture in the marriage, she said: “That had enormous repercussions. After that cameo I moved out of the house with my children. So it didn’t go well. It never went smoothly when I worked.’’

But they were reconciled and she moved back in. And if things were sometimes rocky, she was nevertheless stunned by the suddenness of the breakup. “You don’t spend years with someone and they’re just Photoshopped out of your life,” she said.

She noted what she considered to be a paradox: Mr. Perelman, she said, was attracted to her because she was a movie star, but objected when she wanted to keep making films. “It’s that old thing, you are drawn to a person for certain reasons, and then they try to change you,’’ she said.

Single again, she has started a film production company with her brother, George Barkin, and it is into that enterprise that she plans to channel the proceeds from the sale of her jewelry.

Friends say that Ms. Barkin is resilient. Putting the baubles of the marriage up for auction is a way of bouncing back, said Diane Von Furstenberg, the designer. “That was very healthy,’’ Ms. Von Furstenberg said. “Now she can be herself.’’

She has lost almost 10 pounds since the divorce, and looked girlishly slender in a black Rick Owens T-shirt and Yohji Yamamoto trousers, swinging a leg elastically over the back of the sofa in her trailer.

Her expression, too, was in animated contrast to the Restylane mask worn by many women in Hollywood. She has a habit of scrunching her features — lips compressed, eyes squeezed to slits — buying time to reflect before answering even innocuous questions.

That signature expression was in place even while describing her jewelry, much of which she said she chose herself. Many of the pieces, like a seven-strand natural pearl necklace and a 15-carat diamond ring, are chunky and audacious. They are “unapologetic, I guess,’’ Ms. Barkin said, “And I wasn’t precious about wearing my precious jewels.’’

She routinely wore a 16.94-carat diamond pendant, valued at $600,000 to $800,000, to bed. Several years ago, she was seen at New York fashion shows absently fidgeting with a nickel-size diamond ring.

Except for a diamond ring given to her by Joel Rosenthal, the designer of JAR, whom she considers a friend, she is parting with all the jewelry from the marriage, eager to shed the image of a gem-freighted trophy wife.

“I am not a fantasist,’’ she said. “And certainly, I was never the little girl who dreamt about some rich guy buying her jewelry.’’

The younger of two children in a lower-middle class Jewish family, she grew up in Kew Gardens Hills in Queens. She has boasted in other interviews of fistfights with gangs of girls in the neighborhood. “I certainly wasn’t a thug,’’ she said. “But my mother worked, my father worked. You learned how to take care of yourself. I was as tough as I needed to be.’’

Something of that scrappiness surfaced in her 20’s, during stints as a downtown waitress working in a string of restaurants run by the New York nightlife impresario Mickey Ruskin, the owner of Max’s Kansas City and the Ocean Club. “I was feisty, sure,’’ she said, unabashed. “If somebody didn’t leave a tip for a waitress and that waitress wasn’t me, I would follow them out the door, yelling ‘Was something wrong with your service?’ ”

She was thorny on movie sets as well, known to stalk off in tears when her lines didn’t suit her, but fiercely intent, those who worked with her say, on giving every part her best. Her ferocity led Gordon Cotler, the writer and a producer of a television movie in which she appeared, to predict in 1993, in a letter to The New York Times, that “if some producer didn’t strangle her first, she would be a star.’’

Despite memorably sexy roles, and a reputation as an actor’s actor, Ms. Barkin never attained the A-list stature of Michelle Pfeiffer or Julia Roberts. Since marrying Mr. Perelman, she has taken on only a handful of bite-size parts, notably in the 2004 film “Palindromes,” in which she played the anguished mother of a wayward teenage girl.

She did not fight to land her latest role as a curtly efficient assistant to Mr. Pacino in “Ocean’s 13.’’ “I’ve never been ambitious,’’ she insisted. “I’m a big believer in being in the right place at the right time.’’

She ascribed the recent upturn in her career to luck — and the generosity of the movie’s director, Steven Soderbergh, and one of its producers, Jerry Weintraub.

She was sitting on the beach at a friend’s vacation house after her divorce, Ms. Barkin recalled, mulling over her own contribution to the failure of her marriage, when her phone rang. “It was Jerry asking, ‘How are you doing?’ I said ‘Not so good,’ ” she recalled, her eyes welling. “He said: ‘You’re going to feel better in about 30 seconds. You’re the female lead in ‘Ocean’s Thirteen.’ ”

True, she should have known and it's not like she's starving on the street. But you can still be devastated and hurt by someone, even if you are rich, and it seems from the reportage that this was the case. She had no idea until the day he brought security guards into the house and told her she was gone. Some men have this way of making you feel like you're the only woman on earth, and can be very persuasive, especially if they have the wherewithal to spend a lot of money convincing you...

sou throw me under the bus. Your dangerously close to getting you man-card revoked!

hey, I'm not throwing you under the bus . . . I was just pointing out that the "girl" board favorite Migs was here too. Now, when Stella reads this thread, she's only going to think happy thoughts, not "so why do l let Al-G post here again?"